misinformation from store agent

I purchased a new phone and got a new watch in June(my old watch was no longer charging)….we were in the Panama City Beach store.  We worked with an older female...we are going into the store later today so I will get her name.  She said to get a new watch I could use a promotion...$200 off with the activation of a new line….we questioned using the old line we had for my old watch.  She assured us that in 3 months we could call to cancel the old line...no problem...well we just tried to cancel the old line and we were told that was not an option (Rose..phone agent today)...she said she was sorry and said the store rep should not have told us that and that she hated to give us the "bad news"...she then proceed to try to "offer" us another product to use that line--another phone, watch or tablet...we only wanted to cancel...our other options were if we canceled the old line we would be charged $8.30/mo because the promotion would not be valid anymore, the charge for the line we DO NOT USE IS $12...she said she could give us a reduced charge of $7...again this is nuts...we were lied to in the store and cannot seem to get any resolve...I fell we were lied to, taken advantage of….I an certainly going to shop around and see if I can switch carriers...even for the same price..its the principal….T-Moble certainly does not take care of their customers...so so disappointing…..